Performance problem on Linux but not on Windows with ReBAR v0.3 on Jingsha X99 D8-DDR3 about rebaruefi HOT 6 CLOSED

So 4G decoding is causing fps drop for you ?

0.1 and 0.3 function identically besides the CMOS reset detection. It's probably some other issue or BIOS setting causing the fps drop

from rebaruefi.

Just to be clear, 4G decoding was enabled all the time. As to the performance, I've seen some fluctuation depending on the used BIOS settings (I could get it to 131 fps avg on Linux with some tweaks, but it is still well below 148 fps I got before in that particular benchmark scene).

I don't know if vkd3d-proton or Mesa or other parts of the Linux software stack are contributing to that problem, I saw that vkd3d-proton disables reBAR for some games specifically due to performance problems. I've experimented a lot with different BIOS settings, forcing SAM with RADV_PERFTEST=sam - without success yet. I also already re-installed CachyOS and used the default packages, that also had no effect. I first saw the regression when using the newly-modded BIOS however.

from rebaruefi.

Linux can use resizeable bar without the BIOS supporting it btw, it only needs 4g decoding

from rebaruefi.

I've also seen a lot of PCI-related problems in the past with X99 and Linux, e.g. PCI AER errors when using my i350 network card. I need to use pcie_aspm=off to get rid of that, so there is potential that some obscure PCI problem hits me here, too.

from rebaruefi.

I've now gone back to my old BIOS that used to work fine (edit: I can still reproduce the issue). I found a few differences while comparing the Kernel logs: https://www.diffchecker.com/TL1qvBHp/ (the old BIOS is on the right, the newer BIOS on the left).

1. ACPI tables

• the old BIOS does load a couple more ACPI tables: MPST, MSCT, SLIT, SRAT

2. The values for the PCI bridge window are different (values below are for the GPU)

• for the old BIOS: bridge window [mem 0x383800000000-0x383c0fffffff 64bit pref]
• for the new BIOS: bridge window [mem 0x38f800000000-0x38fc0fffffff 64bit pref]

This is not to say that the ReBar-driver has something to do with it, but I patched the new BIOS file with another tool that also did some other changes that might or might not have an impact here, too.

from rebaruefi.

Closing, as I can still reproduce the issue with the older BIOS.

from rebaruefi.